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Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. TECHNICAL BRIEF
The microphones is placed in the Front cover and contacted to main PCB. The audio signal is for normal
voice call & multimedia functions, Microphone is switched by analog switch(U300), which connects audio
inputs from the microphone to main baseband chip and MMP. The audio signal is passed to MAIN_MICP and
MAIN_MICN pins of AD6726. The voltage supply VMIC is output from AD6726, and is a biased voltage for the
MIC_P. The MIC_P and MIC_N signals are then A/D converted by the voice band ADC part of AD6726. The
digitized speech (PCM 8KHz ,16KHz) is then passed to the DSP section of AD6726 for processing (coding,
interleaving etc). For multimedia functions, these signal processing is done by MMP(AIT716).
3. 9 Microphone
10u
C310
EVLC14S02050
VA300
2
G1
G2
3
O
4
P
1
MIC300
SPU0410HR5H-PB
100nH
L300
2V5_VMIC
100nH
L303
39p
C302
L302
100nH
C309
39p
C303
22n
C300
22n
C305
39p
MAIN_MICP
MAIN_MICN
HANDSET MODE
L
H
MODE
MIC_PATH_SEL
MICROPHONE PATH SELECTION
MULTIMEDIA MODE
0.1uF
C324
C313
1u
2V8_VEXT
C311
1u
C312
1u
NC1
5
7
NC2
2
NO1
10
NO2
1
V+
DG2735DN-T1-E3
U300
COM1
3
COM2
9
GND
6
4
IN1
8
IN2
C319
0.1uF
MM_MICP
MIC_PATH_SEL
MAIN_MICP
MAIN_MICN
VINNORP
VINNORN
Figure 3.9 Connection between Microphone, AD6726 and AIT716